This article discusses 4-week batch farrowing (4WBF), very common in small farms (250 sows) in some other countries, including France. Analysis will be based on a comparison with 3-week batch farrowing (3WBF).

A large part of the work on a swine farm can be divided into 3 key tasks: weaning, mating and farrowing. The day chosen for weaning determines the other two tasks; first, the matings, and then, as a consequence, the farrowings (the 2 ‘great events’ of which productivity of a farm depends on).